<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>盒子模型</title>
    <style>
        #outer{
            /* 可以给每条边框设置单独的样式 */
            border: 10px solid red;

            width:300px;
            height: 300px;

            /* 设置内填充 - padding*/
            padding-left: 50px;
            padding-top: 20px;
            /* 整个盒子的宽度 = 300+2*border+padding-left */


            


        }
    
    </style>
</head>
<body>
    <div id="outer">

    </div>
</body>
</html>